I would sell all my bitcoins if I need money really urgently

Yes you need to sell only if there is any kind of emergency or else its better to save it for future as price will really high in future so selling at the higher price will be more profitable.
I would've answered the same though. I'd sell my Bitcoins if I urgently need money. However, I have another answer.
I would sell all my Bitcoins if I feel that Bitcoin's value is dropping dramatically.
I would just then buy new coins at a lower price.